This application is based upon French Patent Application No. 00 08350, filed on Jun. 27, 2000, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is hereby claimed under 35 U.S.C. xc2xa7119.
1. Field of the Invention
The present invention relates to a comfort upper for footwear adapted in particular, but in a non-limiting manner, to sports such as alpine skiing, telemark skiing, snowboarding, in-line roller and ice skating, as well as for use as a boot for cross-country skiing and snowshoeing. The invention is also directed to the footwear itself incorporating such comfort upper.
2. Description of Background and Relevant Information
In the state of the prior art, especially in the field of alpine ski boots, there are numerous thermoformable liner systems that make it possible to fill the volume located between the user""s foot and the interior of a rigid shell that constitutes the outer frame of the boot. The variation of the liner volume to adjust to the user""s foot can be obtained mainly in two ways. First, a previously thermo-compressed material can be relaxed by heating. Second, the foot can simply compress a heated material that cools off while preserving the shape imparted by the foot, it being possible to perform this operation in a store, i.e., at a sales location.
According to another technique, the liner is entirely constituted of a thermoformable material, and the liner is heated in an oven. Conversely, if the liner includes localized thermoformable inserts inserted in a conventional liner structure, the heating can only occur from within the liner so that the heat does not deteriorate the outer covering of the liner.
In fact, the document FR 2 726 743, and its family member U.S. Pat. No. 5,746,015, improves this system by describing micro-perforations in the thermoformable foam that is inserted in this type of liner. This process makes it possible to optimize the preheating of the foam.
However, the previously described thermoformable liners, which are currently used mainly in alpine ski boots and in-line roller skate boots, i.e., boots having a rigid outer upper or shell, are incompatible with possible stiffeners providing the liner with a certain rigidity. Indeed, the conventional stiffeners to be inserted in the liners or boots are generally made of a non-thermoformable plastic and therefore cannot be adapted to the user""s foot. And even if certain stiffeners can be shaped by thermoforming during manufacture, before assembly of the liner, they conform to a standard foot that does not necessarily correspond to the specific morphology of each user""s foot.
Moreover, the current thermoformable liners cannot be equipped with a tightening system such as laces, because the thermoformable materials used are of the foam type, are flexible and, therefore, are not adapted to resist traction. Furthermore, they do not have an adequate rigidity to properly distribute the localized pressure generated by the lacing at the level of the lace guides. This technology does not make it possible to obtain inner comfort liners equipped with a lacing system by thermoforming. However, this type of liner would be particularly adapted to boots having a flexible or semi-rigid upper and used in particular for snowboarding
Therefore, one of the objects of the invention is to propose a comfort upper for footwear having, in particular, a flexible or semi-rigid outer upper while having a certain rigidity, which makes it possible to adapt to the foot morphology by thermoforming.
Another object of the invention is to propose an upper that makes it possible to comfortably distribute the localized pressure generated by a tightening system associated with the upper of the footwear.
To achieve these objects, the upper of the footwear includes a stiffener made out of a thermoformable material capable of being configured around the user""s foot. This stiffener is positioned between the inner lining, in contact with the foot, and the outer covering of the footwear. In addition, the upper includes a comfort element, positioned between the inner lining and the stiffener, which can be made of a thermoformable material. To better distribute the pressure generated by the fastener of the tightening system, which is arranged on one of the portions of the upper to be brought closer, the stiffener includes at least one arm whose end is positioned substantially beneath the fastener. In addition, the comfort element includes perforations that enable hot air to reheat the stiffener so as to ensure good thermoforming conditions.
In a first embodiment, the perforations open out on the stiffener.
In a second embodiment, the perforations, which are located outside the stiffener, open out on a ventilated layer that is positioned between the stiffener and the outer covering.